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Rivers Aren’t a Problem to be Solved
May 5, 2011 | Floods & Floodplains, Restoring Rivers
Shana Udvardy
Director, Flood Management Policy
[Part 2 of a series on the floods in the Midwest – read part 1 here]
Throughout much of American history, rivers have been treated as problems that must be “solved” through large scale and expensive engineering projects.
The result? Rivers have been clogged with dams, straightened, channelized, and cut off from their floodplains by levees, and even buried underground by agricultural drainage “tiles”.
But these approaches have often exacerbated the very problems they were meant to solve, and have saddled communities with long-term costs they cannot afford.
While building and maintaining flood control infrastructure makes sense for some heavily-populated areas, these individual decisions often have immense negative consequences for decades to come.
Building and strengthening bank armor, levees, and floodwalls creates a levee “arms race.” When one community builds a larger, stronger flood defense, it sends more water (at higher elevations and with more erosive energy) downstream to another community on the river, which then has to respond by building their flood defense larger and stronger. And, this new “economic development” in flood risk areas will come at tremendous costs to the local tax base.
There are few, if any, economic incentives for communities to site new development out of harm’s way.
Instead, when floods strike or a levee fails or overtops, communities can externalize costs to federal taxpayers through federal disaster assistance. We have a moral imperative to think differently about how we respond to flood challenges in a changing climate. By providing incentives to protect our natural defenses (our rivers, wetlands, floodplains, forests and upland and coastal areas), restore our natural areas and replicate green infrastructure approaches nationwide we can reduce flood risk and increase resiliency of both our human and natural communities.
Until we better manage our rivers and improve our flood protection strategies, we will be confronted with crisis after crisis. That is where we find ourselves now, with the Army Corps needing to blow up a levee to save Cairo, Illinois, by sending floodwaters onto Missouri farmland. The fact is, to better safeguard communities and homes, we do need to remove or set back some levees and give rivers more room to spread out and slow down. And by moving or tearing down some agricultural levees, we will have more money and resources to invest in those levees that are most critical for protecting people and homes.
But these decisions should be made as part of a thoughtful, intentional plan for a river and all of its communities – not piecemeal, in crisis, as floodwaters are rising.
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Related Information
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LIBRARY
The Multiple Benefits of Floodplain Easements (06/22/11)
PRESS RELEASES
American Rivers and EPA award $250,000 grant to protect Adams County forests and clean water (04/12/12)
American Rivers and EPA award $163,875 grant to revitalize Waynesboro riverfront (04/12/12)
Comments List
Submitted by Jeremy Nicoletti at: October 19, 2011
I would support the notion that bank modification features can cause significant downstream affects. Take bank armoring for example, or even bridge constrictions: the combination of armored walls and a constricted river valley cause water velocities to increase, and where that armoring ends one can often find an unnaturally wide scour hole. Bank armoring usually has a similar affect. Usually it is built to prevent one bank from collapsing, but since hard armored surfaces do not absorb fluvial energies they are often transported to and concentrated in those areas just downstream of where the armoring ends. Having less experience to levees I will not speak much to that point, but I can vouch from what I have seen on small-scale armoring projects and man-made structures that this is true.
Submitted by Dusty Robinson at: May 5, 2011
While I completely agree with your conclusions about what needs to change in how we address flooding in our country, I would use caution with how one of your argument about the 'hydraulic' impacts of man made defenses. You say that the effects of bank armor, levees, etc. send more water (higher/stronger) downstream to another community. This isn't typically true. The larger impact are to neighboring communities and/or upstream communities, but the downstream effects are often little to none. The hydraulics of a flooding river system can get really complex, and understanding all of the controlling features and effects of specific infrastructure is not a simple matter. I often hear people affected by flooding talk about how this (berm/levee/sandbags) pushed more water onto this land or that building, or some odd description about how water flows during a flood. Most of which are just not reality. All that to say, great article, but be careful building a case on questionable hydraulic assumptions.